Secret-service telephone system.



No. 841,478. PATENTED JAN. 15, 1907.

. A. K. ANDRIANO. SECRET SERVICE TELEPHONE SYSTEM.

APPLICATION FILED AUG 30, 1901.

' 4 SHEETS-$111531 1.

No. 841,478. PATENTED JAN. 15, 1907. A. K. ANDRIANO.

SECRET SERVICE TELEPHONE SYSTEM.

APPLICATION FILED AUG. 80, 1901 4 SHEBTS-SHEET 2. a x i [ride/172x" cwam'rwL cw ML,

A. K. ANDRIANO. SECRET SERVICE TELEPHONE SYSTEM.

APPLICATION FILED AUG. 30, 1901.

4 SHEETS-$831131 a.

PATENTEDDJAN. 15, 190-7".

THE NORRIS PETERS ca., WASHINGTON, n. c,

PATENTED JAN. 15, 1907.

A. K. ANDRIANO. SECRET SERVICE TELEPHONE SYSTEM.

APPLICATION FILED AUG-30. 1901.

4 SHEETS-SHEET 4.

, final Lwmzaruvkmwiwxhm rn: NORRIS Psnrksco" wasmucrou. u. c.

ALBERT KOCH ANDRIANO, OF SAN FRANCISCO, CALIFORNIA, ASSIGNOR,

BY MESNE ASSIGNMENTS, TO DIRECT-LINE GENERAL TELEPHONE COMPANY, OF SAN FRANCISCO, CALIFORNIA, A CORPORATION.

SECRET-SERVICE TELEPHONE SYSTEM.

Specification of Letters Patent.

Patented Jan. 15, 1907.

Application filed August 30,1901. Serial No. 73,801.

To aZ-Z whom, it ntzty concern:

Be it known that I, ALBERT Koon ANDRI- AND, a citizen of the United States, residing in the city and county of San Francisco and State of California, have invented new and useful Improvements in Secret-Service Telephone Systems, of which the following is a specification.

This invention has for its object chiefly to provide a closed metallic circuit for talking between one telephone or station and any selected one of the remaining stationsin the system and by which for the time being an isolated communication between the two stations is secured to such an extent that any person who may attempt to' throw his telephone in circuit with those already in use will be unable to overhear the conversation.

The invention includes further objects and advantages with respect to conservation of battery, simplicity in construction, and in setting up and connecting a number of stations in one system.

The invention comprises certain novel con struction and arrangement of metallic circuits, switching devices, and connections through the action or operation of which any two stations when connected together for talking will have their respective batteries united in a bank or series with the current flowing in the same direction.

The invention consists, further, in novel arrangement of signaling or calling circuits and means at every station through the operation of which the party at a station being called up for talking is notified by a return signal that his instruments are properly connected for talking with the calling-station as soon as he gets the line by moving his switch.

The nature of these improvements and the manner in which I proceed to apply and carry out the same will be explained in the following description, in which reference is had to the accompanying drawings, forming part thereof.

Figure 1 is a planor top view of a switching mechanism for connecting thirty stations in one system in accordance with my invention. Fig. 2 is an elevation of Fig. 1. Fig. 3 is an inverted plan of the base. Fig. 4 1s a detail of the circuit-closer that is controlled by the telephone-hook. Figs. 5 and 6 are diagrams of the circuits of three stations,

illustrating the arrangement of the signaling and talking circuits, the contacts in the switch, and the circuit-closing devices in the circuits of the several stations represented. In Fig. 5 station No. 1 is switched to the line of No. 3 ready to call up that station. In

Fig. 6 the two stations are connected and a circuit ready for talking is completed. Fig.

7 is a diagram illustrating the metallic circuit completed between two connected stations. Fig. 8 is a diagram of the ringing-circuit between two stations.

The switching mechanism herein shown is designed to be placed in the base of a desktelephone.

The views and diagrams illustrate the arrangement and operation of the present system with sufficient clearness to enable any desired number of stations within the scope of the switching mechanism to be installed in one system without further explanation than that herein given.

The parts of the mechanism employed are hereinafter referred to in the specification as station-contacts a. movable contact I), lines-wires d e j, inductron-coi g, and battery h. The transmitter is designated by the letter W, and-the receiver by is. The ringing-key a, bell p, ringing-battery .9, ringing-circuit t u, and telephone-hook to comprise the other principai parts of the mechanism.

At each station the hook to is in metallic connection with the movable contact bof the switch, as indicated at 2, and with the movable stop 3 of the ringing-key. as indicated at 4.

One side of the battery 71. is connected to the line through the movable contact I) by a spring 5, which closes the line touched when the arm of the telephone-hook w is allowed to rise. In the opposite position, however, with the receiver on the hook the contact at 5 is broken. The opposite side of the battery 72 is connected when relations are established for talking with or to the line individual to the station through the wires 8 and 9 and the circuit-closing stops 13 14. The line-wire individual to the station terminates at the first stationary contact in the row a, usually termed the home contact. Connection is also made between one side of the battery s and the line individual to the ICO closers 13 14 before mentioned, which are so placed with relation to the movable contact I) of the switch that when the latter is at rest on its own line -.contact it will disconnect that line both from the ringing battery and the local battery h by opening the circuit at 13 14, or, on the other hand, it the switch 5 be moved the connection at 13 14 will be made and. the circuit closed between the line and the ringing-battery on the one hand and the local battery 7L on the other.

The transmitter m and the primary ot the induction-coil g nay be placed at any point in the circuit; but I prefer to place them as shown'in the diagrazrs Figs. 5 and '6-that is, with the trans .nitter in the line 7 between one side of the battery It and the stop 5 at the hook and the prinary coil in the line 8 9 between the opposite side of the battery and the'hoine contact a. This arrangement of circuits and battery is the same at all the stations, and consequently when two stations are connected with each other by setting the switch of each station to the line of the other station it will be seen that the bat teries, the transriiitter, and the primary or" the inductioncoil oi the two stations will be connected in full metallic circuit comprising the line-wires of the two stations and the local connections at each station. In that circuit the two batteries are connected in series or in such manner that the current from both will flow in the same direction.

The signal provided at each station is the usual bell 29. It is directly connected to one side of the ringing-battery s by the conductors u 15; but'with'the opposite side the connection is made through the conductors 16, 4, and 2, the switch-arm h, the line-wire, and the connections at the other station. In the conductor 16 are placed the circuit-clos ing springs 19 20, controlled by the telephonehook, while between the conductors 16 and 4 is the ringing-key "/1. Under this arrangement the person at the calling-station on pressing his ringing-key after having set his switch. will complete a ringing-circuit with the opposite station through the battery s and the signal 1) at the moment the movable stop touches the back-stop, as will be obvious from the diagrams, Figs. 5 and 8.

Here the movable contact 7) at station No. 1 is represented as set to that one of the station- .ary contacts a to which the li ne f of station No. 3 is attached, so that the bell at No. 3 will ring thence through the line f to the correspond rings again, which it will do as soon as the movable contact touches the stationary contactthat is, the terminal at his switch of the line-wire individual to the calling-station the circuit being as shown in Fig. 5 viz., from one side of the ringing-battery s over the conductors u 15 to the bell p of the called-up station, through the conductor 1.6, over the circuit-closers 19 20, the stops 18 and. 3, connections 4 and 2, the movable contact l), which has now been moved to the dotted-line position, thence along the linewire (1 to the home contact a, at the calling station. From this point the circuit continues over the circuit-closers 18 14, connections 9 and 8, through the primary coil g, through the battery h, which for greater efficiency is set up so as to connect in series with the ringing-battery, thence over the conductor 7, through the transmitter m, the circuit-closer 5, the hook to, connector 2, movable contact I), stationary contact a, upon which said movable contact rests, and along the line-wiref to the called station No. 3, where the circuit is completed through stationary contact a, circuit-closers 13 14, conductor 2]., circuit-closers 12 10, and wires 24 and t to the other side of the ringing-battery 8. When the bell rings at station No. 3, as described, the called party removes the receiver from the hook, and the hook rising to the contact 5 connects in his transmittingand receiving apparatus at the same time that it breaks the bell-circuit by opening the closers at 10 12 and 19 20. The bell naturally continues to ring until the receiver is taken from the hook, when, being cut out, it stops. This method, however, can only be employed when the battery or other source of energy at s is very strong or at least strong enough to operate the bell at the called station despite the resistance of the transmitter coil at the calling station; otherwise the proper way to signal is to do so before removing the receiver from the hook at the calling-station. In that event the current can flow without obstruction, viz: from one side of the battery 8, over the wires u and 15 to the bell p at station No. 3, through the bell, the Wire 16, past the cir cuit-closers 19 20 and. the stops 18 and 3, the connectors 4 2, the movable contact I), stationary contact on which it rests, the linewire cl, to the stationary contact a at station No. 1, thence over the circuit-closers 13 14:, the connector 21, circuit-closers 12 10, wires 24; and t, to the other side of the battery 8. At the same time the bell at the calling-station will ring, thus notifying the operator that the party at the called station is searching the line of the called. This circuit is as follows: from one side of the battery .9, over the line-wire it, through the bell p at station N o. 1, thence over the wire 16, through circuit-closers 19 20, stops 18 3, connections 4 and 2, movable contact I), and out over the line-wire f to stationary contact a at station No. 3, thence over the circuit-closers 13 14, the wire 21, circuit-closers 1.2 10, and wires 24 and t, to the other side of the battery 8. As soon as the operator at station No. 3 begins switching this last-described circuit is completed by the closing of the circuitclosers 13 14 at station No. 3, and the bell at station No. 1. continues to ring until the operator at No. 3 has completed his circuit, as described, so that the bell at No. 3 rings, and has taken down his receiver. moval of the receiver from the hook at No. 3 the ringing-circuit is broken at 10 12 and 19 20, and the resistance of the transmitter at No. 3 being thrown into the circuit the bell at No. 1 will stop ringing (unless the source of energy at s is purposely made strong enough to overcome it, as already described) and the operator at No. 1 will know that the party at No. 3 has found the line, has removed his receiver, and is ready for talking. The bell at No. 3 has stopped ringing as soon as it is cut out at 19 20 by the rising of the hook.

When the local talking-circuits of stations Nos. 1 and 3 are connected to the line-wires df, which takes place as soon as the switcharms I) have been properly adjusted and the receivers are taken down for use, a full metallic circuit is formed between the two stations in which the two banks of batteries h are connected in series, with the effect to cause the current to pass from the positive side of one battery into the negative side of the battery at the opposite station, where it passes out at the positive side and back to the other station and finally completes the circuit at that station to the negative side of the first-mentioned battery. When these conditions are set up between two stations, a party at any other station (say station No. 2 in the diagrams) Will be unable to switch in and listen to the conversation, for the reason that he can get only one side of the circuit and also because as a consequence he can get no battery. In order to listen on a busy circuit it would benecessary to connect with both sides of it. For instance, to listen to conversation between Nos. 1 and 3 it would be necessary to connect one side of the transmitter or talking circuit to the linew.ire (Z and the other side to the line-wiref, and this in the present construc- Upon the re- &

tion is manifestly impossible, because one side of the local circuit at station No. 2 is perrnanently connected to the line-wire c. This makes it impossible to listen in or interrupt as well as to secure the necessary batterypower to operate the instrument. One can therefore only make connection with another instrument by the completion of the circuit through the assistance of the operator of the called station. A closed metallic circuit is set up between any two stations properly connected, and this will not interfere with like operations of switching, calling, and connecting between any of the remaining stations. In addition to the'privacy thus afforded this system has the advantage of preventing exhaustion of battery through carelessness in leaving the receiver off the hook after use, for the circuit through the battery h stands normally open and is not closed until connection is made with the circuit and battery of another station by the operation of switching.

Figs. 1, 2, 3, and 4 represent a construction of switching mechanism and circuitclosing devices in the base of a portable switch-stand for a desk-telephone outfit. The movable contact of the switch and the circuit-closers are controlled by the arm of the hook w in such manner that the talkingcircuit is completed and the ringing-circuit is opened as soon as the receiver is removed from the hook after the movable contact I) has been set, and, on the other hand, the movable contact is automatically returned to the home contact and the ringing-circuit is restored to the line for action when the receiver is hung up.

It should be mentioned that the switching mechanism herein shown is similar to that described in Letters Patent No. 691,229, which were issued on the 14th day of January, 1902, to Albert K. Andriano and Hermann Herbstritt, particularly in the general construction and operation of the stationary contacts and movable contact and the means employed for moving and locking the movable contact and for returning it to the home contact on hanging up the receiver. In the present switch, however, the arrangement of the circuit-closing springs in the connection between the local circuit and the line of the station and also the connections between the local bell-circuit and the common ringing battery are different in some respects from those in the construction before mentioned, so that a description and illustration of those features are here supplied. It should be understood, however, that it is not intended thereby to limit or restrict the present invention to the particular form or character of switching mechanism herein described, because the system is capable of being operated by other well-known switching and circuitclosing means, whether the same be actuated or controlled by the movable member of the switch or otherwise.

The stationary contacts a are fastened on insulation-segments 30, composed of separate pieces secured to the circular base. The post 31, on which the movable contact 17 turns, is hollow, and the wires of the primary circuit and bell-circuit are carried from the bindingposts to the circuit-closing springs through the post instead of over the top of the frame, as heretofore.

A shaft 33, connected with the movable contact by spur-gears 34 35, furnishes the means for setting the movable contact, and a dial 36, attached to the arm of the movable contact, indicates by the number it exposes to view at the sight-aperture 37 the position of the contact with respect to the stationary contacts beneath.

The yielding plate 32 constitutes one member of a circuitcloser,of which the other member is the spring 5. When in an elevated position, being pressed upward by the coiled spring 39 on the guide-post 38, the plate 32 touches the spring 5 and closes the circuit; but as long as the receiver is left on the hook its weight, operating through the rod 38, holds down the plate 32 and keeps the circuit open.

The tubular rod 38 is attached at the upper end to the arm of the telephone-hook, which is not shown in the drawings, and fits closely over the post 38*, resting on the top of the plate 32, as seen in Fig. 4. The local circuit is thus closed by removing the receiver from its hook, or it is opened by hanging up after talking is ended.

The circuit-closing springs 10 12 and 19 20, that control the ringing-circuit, as already described, are opened and closed by the same movements of the plate 32 through the following means: In a block 40 of insulating fiber carried by the plate 32 are fixed two circuit-closing pins 41 12 on opposite sides and directly over the line of separation between the springs, which are likewise situated in pairs on opposite sides of the plate 32. The ends of the springs in each pair are normally out of contact; but as the plate 32 is depressed the pin in line therewith makes metallic contact with both springs as it passes between their ends. The circuits controlled by these springs 10 12 on one side and 19 20 on the other side of the block 10 are the local circuit of the subscribers bell and the connection with the ringing-battery, as will be seen by referring to the diagram Fig. 6.

In that arrangement of circuits and cir cuit-closing means which are employed in connection with a wall-telephone the springs 10 12 19 20 are situated in close relation to the arm of the telephone-hook, which. by contact with the springs when depressed by the weight of the receiver brings the springs in contact and holds the ringing-circuit closed on the bell ready for action or' as the receiver is removed from the hook the arm rises and allows the springs to separate.

The arrangement illustrated in Figs. 2, 3, and 4, on the other hand, applies to a desktelephone, in which the switching mechanism and circuit-closing means are located in the base. In this instrument the movable stop of the ringing-key is attached directly to the rotatable spindle 33, that is connected to the movable arm or contact I) of the switch by the gears 34 35, and being fitted to move longitudinally, as well as turn axially in its bearings in the frame, the spindle has the function of a ringing-key as well as a switchoperating device. After setting the switch to the required number the party at the callingstation closes the ringing-battery circuit on the bell of the opposite station by pressing down on the spindle before he takes his hand. off the knob n. This construction combines in one device the switching and calling device heretofore made of separate parts and requiring two separate movements of the hand to operate.

In the operation of connecting one station with another it will be noticed that the batteries h of the two stations are connected in series in the metallic circuit, which is formed and completed as soon as the respective switches b of the two stations are placed on the proper contacts in the switches to select the lines that complete the circuit; also, that the transmitter at each station is interposed between its own battery and the battery of the opposite station through the peculiar arrangement of the switches and connections. This will be understood from the diagram Fig. 7, in which it will be noticed that the transmitter side of the battery, being connected to the movable contact 6 of the switch, is through that part directly connected to'the line of the station to which the switch may be set, while the primary of its inductioncoil, being connected to the line of the station by the act of moving the switch away from it's own line-contact, the two sides of the battery are closed on the two lines (Z f. One of these is the line of the calling-station and the other that of the other station called up.

The complete operation of switching thus requires the arm 6 of the switch at both stations to be moved each off its own line and set to that of the other station. In doing this the party at the station called up proceeds to search for the line of the station calling him by moving his switch-arm from one point to another in the switch until it touches the switch-point belonging to the line of the other station. When that is done, a ringingcircuit is again completed over the line-wire of the calling-station and the bell will ring a second time at the moment that his switch touches the line-contact of the other station IIO and will continue to sound until the party opens his bell-circuit by taking the receiver off its hook.

The manner of connecting the bellcircuit in the ringing-b attery lines and with the talking-circuit lines to operate the return-signal will be understood by referring to Fig. 8, in which the calling-station on the left of the diagram has switched to the line f of the station on the right and is ringing up that station.

As the movable stop 3 of the ringing-key at the calling-station is pressed against the back-stop 22 it connects one side of the ringing-battery s to the line f, that now is the onlyconnecting-line between the stations being considered. The circuit from the negative side of the battery 8 may be traced along the wire t, the conductors 24 and 23 at the calling-station to the baclestop 22, thence by the conductors 4 and 2 to the movable arm I) of the switch that rests upon the terminal contact of the line f. Tracing the circuit at the called station and starting with the terminal contact there, which is the home contact of that station, upon which the switch arm I) normally rests, it follows the conductors 2 and 4 to the movable stop 3 of the ringing-key that is in normal engagement with the front stop 18, thence by the conduc tor 16 to the bell, and from the bell by the wire 15 to the lead it, that connects with the positive side of the battery 3. This causes the bell p at the called station to ring. Hearing this, the party at that station moves the switch-arm I) of his switch successively over the stationary contacts (1 until that one is reached that is the terminal of the line d that is individual to the station calling, this position of the parts being indicated by dotted lines at the righthand station of Fig. 5. As soon as the stationary contact of this line is touched by the movable arm of the switch his bell will again ring, a new circuit being established, this circuit being difierent in part from that first established and may be traced as follows: Starting from the positive side of the battery 5 and passing by the wire 15 to the bell p of the called station, thence by the wire 16, the movable stop of the ringing-key, the conductors 4 and 2, leading to the switch-arm that now rests upon the stationary contact of the line d, thence by such line to the calling-station, thence by the contact device 13 14 to the conductor 21 24, which in turn connects with that lead tof the ringing-circuit that goes to the negative side of the battery.

The practical operation of the system herein described has demonstrated that when two stations are connected in the manner described there is no interference from induction, there being an entire absence of buzzing or other objectionable sounds in the instruments, while the speech is transmitted with remarkable clearness.

It will be observed that when two stations are connected for talking the batteries by which the current is supplied to the line are not only arranged in series, as has been described, but are separated and have the telephone instruments arranged between them, thus balancing the line, thereby permitting a more delicate adjustment of the instruments and a more ready response to the current that may be sent over the lines than if the entire battery force were generated at a single point.

It is well known that when two conductors over which pass electric currents are arranged parallel to each other there is liable to be more or less disturbance in the lines inoident to induction if the lines are in proximity to each oher. It is also well known that the effects of such induction may be largely re duced if the positions of the lines with reference to each other are transposed, which is commonly done by crossing the lines at intervals, so that one will lie first on one side and then on the other of its neighbor.

It will be observed, particularly by reference to Figs. 6 and 7, that there is a transposition of the lines of the circuit connecting two stations produced by the act of connecting them by their switching devices, and I am led to believe that the absence of induction, which it has been demonstrated is an important l eature of the system herein described, is partly due to this transposition of the'lines connecting the stations.

It is apparent that in the form of the invention herein illustrated there is not a complete circuit at the local or subscribers station, including the local battery, the telephone instrument, and those connections by which the partial, broken, or incomplete circuit at the station is connected with the linewires, and thus made a part of a complete circuit, including the instruments at the two connected stations. I, however, employ the phrase local circuit in some of the claims hereof and mean thereby the circuit elements at the local or subscribers station, though they may not of themselves form a complete or closed circuit,

Vhat I claim is 1. In a telephone system, having the stations interconnected by line wires and switching devices, the following instrumentalities in combination, viz., a source of electrical energy, a telephone instrument connected with one pole thereof, a switching device, means for connecting the telephone instrument with the switching device whenever such instrument is taken down for use, and means controlled by the switching device for making connection between the other pole of the source of energy and another line ICO - following instrumentalities for each station,

namely, a battery, a telephone instrument connected with one side of the battery, a switching device arranged by adjustment to be brought into connection with the contact of a line leading to another station, means connecting the said switching device with the telephone instrument when it is desired to use the latter, and means controlled by the switching device for connecting the other side of the battery with the contact of the line individual to the station when the switching device is removed therefrom, whereby when the switching devices at two stations are each connected respectively with the line individual to the other station a complete metallic circuit is established uniting the batteries at the local stations in series, substantially as set forth.

3. In a telephone system, stations each having a local circuit including a battery and a telephone instrument, a switching device, for connecting the station with another selected station, comprising contact-points that are terminals of the lines leading to other stations in the system and a movable contact to which one side or terminal of the local circuit of the station is connected when the parts are in position for talking, and circuit-closing means controlled by the movable contact of the switch and operating to connect the other side or terminal of the local circuit to the line individual to its own station when the movable contact has been moved away from its home contact to make connection with another station,,substan tially as set forth.

4. A telephone system having stations connected by line wires and individual switching devices containing contact-points for said lines and a movable contact, a local circuit at each station including a battery, both sides or poles of which are normally disconnected from any of the line-Wires when the parts of the apparatus at the station are in their normal positions of rest, circuit-closing means for connecting at will one side of the battery to the line of the station, and a second circuit-closing means ada ted by adjustment to connect the other si e of the battery to the line of another station through the switching device.

5. In a telephone system having stations connected through line-wires and switching devices, the combination, at each station, of a local circuit including a battery, a switching device to which one side of the local circuit is connected, and means for connecting the other side of the local circuit to the line of the station, comprising a circuit-closing device operated by the movement of the sta tion switching device to disconnect such circuit from the line while the switching device is resting on the line-terminal of the station, and to connect the circuit to the line whenever the switch is set to the line-terminal of another station.

6. In a telephone system, stations having each a local circuit including a transmitter, an induction-coil and a battery, a switching device containing stationary switch-points for the lines of all the stations and a movable contact to which one side of the local circuit of the station is connected, and circuit-closing means in the connection between the other side of the local circuit and the switching device, operating by the adjustment of the movable member thereof to connect that side of the local circuit to the line of the station, said connection being broken by the circuit-closing means when the switch is normally resting on its own line.

7. In an interconnecting system of transmitting and receiving telephonestations, a local circuit including a battery, a transmitter connected to one side of the battery, and an induction-coil having its primary windings connected to the other side, a switching device containing stationary switch-points providing terminals for the lines of all the stations interconnected through said switch and a movable contact to which the transmitter side of the battery-circuit is connected, and a circuit-closing device adapted to connect the primary windings of the induction-coil to the line of its own station when the movable contact of the switch is set to the line of another station, saidswitching and circuit-closing devices being adapted by such adjustment to connect the local-battery circuit to the line of the station and to that of the other selected station in a metallic loop having the transmitter and the primary windings of the'induction-coil at each station connected in series with those of the opposite station.

8. In a telephone system, the combination with a plurality of stations, each interconnected through line-wires and switching mechanism, of a talking-circuit at each station comprising a battery, an induction-coil, a telephone instrument, and means controlled by the switching mechanism for closing the talking-circuit to the line of the station when the switching mechanism is operated to connect with another station.

9. In a telephone system having stations connected through line-wires and switching devices, the combination of the local talkingcircuit, and means for connecting one side of the local circuit to the line of that station,

by the movement of the station switching device to disconnect the said local circuit comprising a circuitclosing device operated from the line while the switching device is resting on the line-terminal of the station, and to connect that circuit to the line when the switch is set to the line-terminal of an other station.

10. In a telephone system having stations connected through line-wires and switching devices, the combination of the local talkingcircuits, batteries, one for each local circuit, and means for connecting one side of the 10- cal circuit to the line of that station, comprising a circuit-closing device operated by the movement of the station switching device to disconnect the said local circuit from the line while the switching device is resting on the line-terminal of the station, and to connect that circuit to the line when the switch is set to the line-terminal of another station.

11. In a telephone system, line-wires terminating at stationary contacts at the local station, switching devices at the stations each having a movable contact adapted to engage with the said stationary contacts,the local talkingcircuits each connected on one side with the movable contact of the switching device, and on the other with the individual line of that station, and a circuitbreaker in the last said connection arranged to be operated to open the circuit when the movable contact is on its home contact and to close the circuit when it is moved therefrom.

12. In a telephone system, line-wires interconnecting the stations, switching devices at the stations for connecting the local circuits with the line-wires, batteries one for each stal ion, both sides or poles of which are normally disconnected from any of the linewires when the parts of the apparatus at the station are in their normal positions of rest, and means at each station for connecting one side of the local circuit to one of the line-wires and the other side of the local circuit to the other line-wire between two select ed stations when such stations are connected through. their respective switching devices, whereby the line-wires of the two stations thus connected will complete a metallic circuit unit ing them, the batteries for the stations being included in said circuit in series.

13. In a telephone system, wherein the sta tions are interconnected by means of linewires having terminals at the stations, and switches at the stat ions for making contact with any selected one of the said terminals, the iollowing instrunientalities at each station,namely, a local calling device or signal, means for connecting the signal with one side of the source of electric energy, a make-and break device with one contact of which the signal is connected when the station is not connected for conversation, including the se lecting-switch of the local station, and connections with the other side of the source of electric energy and the second contact of the makeandbreak device, substantially as set forth.

14. In a telephone system, stations interconnected by means of line-wires and switches at the stations, a local calling and signaling circuit at each station connected on one side with a source or electric energy, and means for connecting the other side of such circuit with the remaining side of the source of energy through the movable member of the switch of one of the connected stations, the line-wire individual to the other connected station and connection at the latter stalion independent of the movable member of its switch, but controlled thereby, being open when the station is not busy and closed when connection is made with the line of another station.

15. In a telephone system, the line-wires between the stations terminating at contacts at the local stations, switching devices at the stations, each having a movable contact for engaging the terminal contacts, local calling and signaling circuits, each local circuit being normally connected with a movable contact of the switch of that station, and a connec tion between the line individual to each station and the source of energy for the cal]- ing-circuit, including a circuit making and breaking device that is opened when the movable contact is on the home terminal contact and is closed when it is moved off therefrom, substantially as set forth.

16. In a telephone system, individual line wires connecting the stations, switching devices at each station arran ed by adjustment to connect with a line individual to another station, a local signaling and calling circuit at each station, each circuit being connected on one side with a source of energy and on the other side connected with the movable me1nber oi the switch of its station, and connections at each station between the opposite side of the source of energy and the line individual to that station, the latter connections being controlled by the movable member of the switch, being opened or broken when the switch is on-the contact of the line individual to that station and closed when the switch is moved oil such contact, substantially as set forth.

17. In a telephone system, the line-wires between the stations terminating at stationary contacts at the local stations, switching devices at the stations each having a movable contact for engaging with the said stationary contacts, the local ringing-circuits, each normally connected on one side with the movable contact of the switching device and on the other with one side of the source of energy, a circuit making andbreaking device in the firstanentioned connection, a connection between the opposite side of the source of energy and the movable contact arranged to be closed by the said circuit making and nal by moving the movable contact upon the breaking device when it is operated to break stationary contact of the line of the calling; the normal connection with the local calling;- station. circuit, and another connection between such l In testimony whereof I have signed my 5 side of the source of energy and the line indil name to this specification in the presence of 15 vidual to the station arranged to be closed l two subscribing witnesses. when the movable contact is moved oil the ALBERT KOCH ANDRIANO. home contact, but to be opened when the Witnesses: movable contact is at rest thereupon, where- N. T. HEss,

:o by the station called can cause a second sig- I E. MYRON l/VOLF. 

